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    Subject[PATCH 5.10 213/452] media: pvrusb2: fix array-index-out-of-bounds in pvr2_i2c_core_init
    Date
    From: Pavel Skripkin <paskripkin@gmail.com>

    [ Upstream commit 471bec68457aaf981add77b4f590d65dd7da1059 ]

    Syzbot reported that -1 is used as array index. The problem was in
    missing validation check.

    hdw->unit_number is initialized with -1 and then if init table walk fails
    this value remains unchanged. Since code blindly uses this member for
    array indexing adding sanity check is the easiest fix for that.

    hdw->workpoll initialization moved upper to prevent warning in
    __flush_work.

    Reported-and-tested-by: syzbot+1a247e36149ffd709a9b@syzkaller.appspotmail.com

    Fixes: d855497edbfb ("V4L/DVB (4228a): pvrusb2 to kernel 2.6.18")
    Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
    Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
    Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/media/usb/pvrusb2/pvrusb2-hdw.c | 7 +++++--
    1 file changed, 5 insertions(+), 2 deletions(-)

    diff --git a/drivers/media/usb/pvrusb2/pvrusb2-hdw.c b/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
    index 3915d551d59e..fccd1798445d 100644
    --- a/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
    +++ b/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
    @@ -2569,6 +2569,11 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
    } while (0);
    mutex_unlock(&pvr2_unit_mtx);

    + INIT_WORK(&hdw->workpoll, pvr2_hdw_worker_poll);
    +
    + if (hdw->unit_number == -1)
    + goto fail;
    +
    cnt1 = 0;
    cnt2 = scnprintf(hdw->name+cnt1,sizeof(hdw->name)-cnt1,"pvrusb2");
    cnt1 += cnt2;
    @@ -2580,8 +2585,6 @@ struct pvr2_hdw *pvr2_hdw_create(struct usb_interface *intf,
    if (cnt1 >= sizeof(hdw->name)) cnt1 = sizeof(hdw->name)-1;
    hdw->name[cnt1] = 0;

    - INIT_WORK(&hdw->workpoll,pvr2_hdw_worker_poll);
    -
    pvr2_trace(PVR2_TRACE_INIT,"Driver unit number is %d, name is %s",
    hdw->unit_number,hdw->name);

    --
    2.35.1


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